Die



Jan. 16, 1940. F. P. JACKSON DIE Filed Aug. 4, 1938 ail/Mm a/wdlAMu f 1 I g any Patented Jan. 16, 1940 PATENT OFFICE P. Jackson, Austin, Tex. Application August 4, 1938, Serial No. 223,087

'7 Claims.

This invention relates to dies.

It has been proposed to provide dies of various types; for punching holes in paper but the cutting edges of the dies are sheared off at an angle .on one face so that the chips are crowded into the die and-due to the enormous pressure dies frequently split or crack. Attempts have also been made to provide curved inner sidewalls adjacent the cutting edges for causing the chips to bend when they pass through the throat of the die. However, the edges of the chips are compressed against the curved faces at each cut by the subsequent chips so that the walls of the. cutter are spread apart. Attempts have also been made to provide cutters with an ex- ..tremely shortthroat and in which thecutters are formed as a unit and mounted in a block. Such cutters being provided with one face only sheared at an angle will cause the chips to be forced under considerable: pressure through the cutting unit and cause distortion of the unit and dislodgement of said unit from the holding block. g It is an object of the present invention to provide a punch for forming U-shaped slots in the edges of ,stacks of papers in which the opposite faces .of the. cutter are sheared off at the same le so that when the punch is forced through the papers the pressure will be equally distributed. g Another object of the invention is the provision of a punch for cutting U-shaped slots in Stacksof paper inwhich one wall of the shank forms part of the/cutter with parallel sides projecting from said portion of the shank with a bridging member. connecting the two parallel portions at their free ends, the parallel portions and the adjacent end of the shank being sheared off upontheir opposite faces to provide cutting edges, the bridging member being devoid of a ,cutting edge, the punch having a relatively short throat which-opens at its upper end into a cutout portion of the shank. Afurther object of the invention is the provision of a punch whichincludes a shank having one face inclined inwardly from its upper end 5 to its lower end with the opposite faces of the .shank being rounded and forming at its lower end, one wall of the punch, side walls projecting laterally from the, lower end of the shank and connected at their outer free ends by a bridging member, the side walls and the reduced end of the shank being sheared off at its oppo- -sitefaces to provide cutting edges in such a unanner that a plane passing through the cutting edges of the lower portion of the shank and the sidewalls forms equal angles with the inner and outer faces, the inclined wall of the shank being provided with a longitudinal groove which extends into the throat at the upper end 1 of the shank to cause the chips to move upwardly and be spread apart at points where they contact the longitudinal groove, the lower end of the bridging member being blunt.

This invention will be best understood from .a consideration of the following detailed description, in view of the accompanying drawing form- .punch in operative position for punching U- shaped slots in stacks of paper,

Figure 2 is a vertical section taken centrally through the punch,

Figure 3 is a fragmentary front view in elevation of the punch,

ure 4 is a vertical section taken along the line 4-4 of Figure 2, and

Figure 5 is a bottom plan view of the cutter. i ure 6 is avertical section taken along the line 6-6 of Figure 1. Referring more particularly to the drawing,

llldesignates a shank having substantially flat walls I! and I2, a curved rear wall l3 and a front inclined wall H.

The upper end of the shank is provided with a shoulder 15 anda member l6 which is adapted to be located within an operating means for the punch.

The cutter, generally designated by the numeral 20, has a curved rear wall 2| and straight sides 22 and 23. A bridging member 24 connects the front edges of the side walls and ter- -minates short of the lower ends of the side walls and the curved rear wall 2!, as shown at 25.

The inclined wall N forms with the throat, 26 a discharge for the chips as they have been cut from they stacks of paper 21.

The inclined face M of the shank I0 is provided with a longitudinal groove 30 which extends from the upper end of the shank down into the throat of the cutter so that this inclined Wall is transversely curved substantially throughout its length.

It will be noted from Figs. 2 to 4, inclusive,

that the curved rear wall 2| of the cutter has its inner and outer faces sheared oil at an angle so that a vertical plane, designated by the letters AB which passes through the cutting edge 3| of said wall forms equal angles with the inclined faces 32 and 33 so that the angle ABC is equal to the angle ABD. It will also be noted from Fig. 4 that the side walls adjacent their lower ends are similarly sheared at both faces to form the cutting edges 34 and 35 respectively along the lower edges of the side walls 22' and '23. However, the inner faces of the side walls above the widest section, designated by the numeral 36, are inclined outwardly towards the upper ends, as shown at 31, for progressively increasing the width of the throat above the point 36 to facilitate the discharge of the chips. I

It will be noted that the lower edge 25 of the bridging plate 24 falls short of the cutting edges 34 and 35 of the respective side walls 22 and 23' and that this lower edge is blunt and forms no part of the cutter.

It will be seen by the above construction that a punch is provided in which the inner and outer faces of the side walls of the cutter form equal angles with planes passing through their cutting edges so that when the punch is driven through a stack of paper pressures on the inner and outerfaces of the cutter are equalized and thus strain on the cutter is eliminated.

The transversely inclined groove 30 of the wall l4 cooperates with the inclined faces 31 of the walls 22 and 23 to facilitate the discharging of the chips after they have been cut from the stack of paper so that the chips will be readily forced from the cutter and will relieve the walls of the cutter against pressure since the chips spread apart adjacent the longitudinal groove 30 so that they will be dropped continuously over the bridging member 34. It will be also noted that the rear wall of the shank. l0 and the rear wall of the cutter are curved transversely throughout their lengths to facilitate the penetration of the paper by the punch.

Referring more particularly to Figures land 2, it will be seen that a delivery tube is applied to the die and this tube may be either secured to the die or it may be removably attached thereto. The tube includes a throat portion 40 and a chute. M. Said chute is substantially at right angles to the throat and is located at the upper end of the throat.

The throat consists of a front wall 42 and side walls 43. The front wall is provided with a lip 44 which engages over the upper edge of the bridging member 24 and is bent slightly outwardly from the plane of the front wall 42, as shown more particularly in Figure 2.

The lower ends 45 of the side walls 43 overlap the upper inclined edges of the straight sides 22 and 23 of the cutter while the rear edges 46 of the side walls 43 overlap the front edges of the inclined face l4 of the shank Ill. Thus, it will be seen that the throat fairly encloses the cut out portion at the inclined face of the shank.

The chute 4! has side walls 41 and a bottom 43. The side walls 41 merge into the side walls 43. The bottom 48 of the chute forms substantially a continuous portion of the front face 42 of the throat.

Straps 5D and 55 are secured to the side walls 43 andenibrace the rear wall l3 of the shank In. Where the delivery tube is removably mounted on the die the straps frictionally engage the shank and maintain the tube in position.

The chips are discharged from the cutter 20 and are forced upwardly in the expanded or flared throat 40 and then out through the chute 4| whence they are discharged away from the work which is being operated on. It will be noted in Figure 1 that the delivery tube leans outwardly and is inclined at such an angle upon the shank l0 that the chips may be freely carried upwardly as the work progresses whereby they will be forced along the inclined chute.

Referring more particul'arlyto Figures 1 and 6, it will be seen that the upper edges of the strap 50 are provided with inturned flanges which are adapted to engage within grooves 56 formed on the flat walls II and I2 of the shank l0. Since the strap 50 is formed of spring materialthese flanges will snap into the grooves 56 and lock the delivery tube in position on the shank.

By this construction the delivery tube may be tilted inwardly at its upper end toward the shank and then forced downwardly whence the delivery tube maybe readily removed from the shank.

It will be noted from Figures 1 and 2 that when the cutting edge of the die is placed upon a pile of sheets of paper to be punched that the bridging member 20 is spaced a sufficient distance from the outer edge of the sheets so that when the chips reach the upper end of the throat the outer edges of the chips will just about engage the inner wall of the bridging member 20;

It will also be noted from Figure 4 that as the chips pass through the throat of the die they will buckle and they will buckle to a greater extent as they leave the upper end of the throat and this buckling is due to the particular formation of the throat. v

The buckling of the chips causes the chips to pass with greater ease through the throat than if the throat were of the same cross sectional area throughout the length.

The peculiar construction of the punch as evidenced by the reinforcing cross bar 20 and the shape of the inside passage of the die is such as to give the punch strength and hold it in a straight course so that there is no draw" in punching through seventy-five to one hundred sheets at one operation.

I claim:

1. A punch for forming U-shaped notches in stacks of paper comprising a shank having one wall rounded and the opposite wall progressively inclined inwardly from the upper end to the lower end and a cutter at the reduced lower end of said shank, said cutter being approximately rectangular except the rear wall which is a continuation of the round wall of the shank, the wall opposite the round wall of the cutter having the lower edge blunt, the remaining lower edges of the cutter being sharpened to provide a knife edge.

2. A punch for forming U-shaped notches in stacks of paper comprising a shank tapering from the upper end along one edge to the lower end, a cutter projecting laterally from the lower end of said shank and provided'with a substantially.

rectangular opening therethrough to provide vertically disposed walls, one wall of the cutter at the rear being curved transversely, the opposite wall being straight and having a blunt lower edge, the remaining walls having the lower edges sharpened to provide a knife edge.

3. A punch for forming U-shaped notches in stacks of paper comprising a shank, a cutter extending laterally from the lower end of the shank and consisting of a rear wall and a pair of spaced parallel side walls extending forwardly of the rear wall, and a bridging member connecting the outer free ends of the side walls, the lower edges of the rear and side walls being sharpened to form a knife edge, said shank being cut away along one edge and over the cutter.

4. A punch for forming U-shaped notches in stacks of paper comprising a shank, a cutter extending laterally from the lower end of the shank and consisting of a rear-wall and a pair of spaced parallel side walls extending forwardly of the rear wall, and a bridging member connecting the outer free ends of the side walls, the lower edges of the rear and side walls being sharpened to form a knife edge, one edge of the shank being inclined inwardly from the upper end to the rear wall, the lower end of the bridging member terminating short of the knife edge of the rear and side walls.

5. A punch for forming U-shaped notches in stacks of paper comprising a shank gradually reduced in width from one end to the other, a pair of spaced blades having knife-edges and project ing from the reduced end. of the shank and laterally therefrom, the reduced end of the shank having a knife edge in the same plane with the knife edges of the blades and cooperating with the blades to form a cutter and a bridging member connecting the free ends of the blades.

6. A punch for forming U-shaped notches in stacks of paper comprising a shank gradually reduced in width from one end to the other, a pair of spaced blades having knife-edges and projecting from the reduced end of the shank and laterally therefrom, the opposite faces of the blades and the reduced end of the shank being sheared off at an angle to provide knife edges at the outer ends of the blades and reduced end of the shank, a vertical plane passing through each knife edge forming equal angles with the sheared off portions.

7. A punch for forming U shaped notches in stacks of paper comprising a shank gradually reduced in width from one end to the other end to provide an inclined face, a pair of spaced blades having knife edges and projecting from the reduced end of the shank and laterally therefrom, the reduced end of the shank having a knife edge in the same plane with the knife edges of the blades and cooperating with the blades to form a cutter and a bridging member connecting the free ends .of the blades, the inclined face having a longitudinal groove extending into the cutter to facilitate the release of the chips.

FRANK P. JACKSON. 

